Abundance and Distribution of Soft Coral in the Great Barrier

Project Overview

The goal of this research is to explore and discuss the correlation between sea temperature and the abundance of soft coral in the Great Barrier Reef. The Great Barrier Reef is located northeast of Queensland Australia. It spans 344,400 km2 and is home to 10% of the world’s coral reefs. Coral reefs create a habitat where marice flora and fauna can florish. These coral beds provide shelter, food, and a breeding place for thousands of marine species inlcuding but not limited to fish, mollusks, rays, dolphins, sea sponges, and birds. The coral reefs have a direct and indirect relationship with the fishing industry, more bleaching means less fish are caught for human consumption. Increases in human population and industrilization has led to an increase of greenhouse gas accumulation in the atmosphere. This increase has been attributed to an increase global average temperature including sea surface temperatures. This increase in sea surface temperature has caused major bleaching events, most notably the summers of 1998, 2002, 2017, and 2020. Roughly 60% of the Great Barrier Reef has succumb to moderate to severe bleaching as of 2020. This means that these coral have released the algae that lives within their tissue, which provides 90% of their energy. Starved of energy for too long these coral will ultimately die off leading to the discintigration of the coral beds. These coral reefs can take 10,000 years to grow, larger ones up to 300,000 years to fully grow. The main research question is how does a change in sea surface temperature affect the abundance of soft corals in the Great Barrier Reef. An additional goal of this analysis is to determine if there is a correlation between coral abundance and different protection statuses in the Great Barrier Reef. The lowest protection is “Protected area with sustainable use of natural resources”, followed by in order by increased use restrictions, “Protected Landscape/Seascape”, “Natural Monument or Feature”“Habitat/Species Management Area”, “National Park”, and “Strict Nature Reserve”,

# Data Overview

The data used for this analysis are observations of octocorals, black coral, and wire coral taken between May 1996 and December 2001. All species that are categorized as soft coral. Data from 1996-2001 was used to observe the changes before and after the major bleaching event that occured in 1998. All observations were taken in northeastern Queensland, Austaralia where the Great Barrier Reef is located. Some of these observations were taken near Heron and Lizard island, areas known for a diverse coral biodiversity. Data was published by Australian Institute of Marine Science and hosted by CSIRO National Collections and Marine Infrastructure Information and Data Centre. The choice for these kinds of coral is because they are often the first coral to succumb to bleaching. Some marigins of error or biases in the data could come from the accessibility of certain reef regions and the available technology at the time. While many locations were visited more than once, not all were visited every year. For example, one location might have only been visited in 1996 and 1999. The time of year can also provide a bias to the data as going out into the water during the colder months (June through August in the Southern Hemisphere) is not always pleasant. Being closer to the equator this is not as big a concern, but is important to note.

Data Visualizations

Figure 3. Boxplot showing the variation of temperatures for each year of temperature observations. There were three stations that provided mulitiple observations for each year. These temperature variations are for the annual temperature of each station.

Figure 3. Boxplot showing the variation of temperatures for each year of temperature observations. There were three stations that provided mulitiple observations for each year. These temperature variations are for the annual temperature of each station.

Figure 1. This boxplot shows how the distribution of observation for different soft coral families between 1996 and 2001. Most families have boxes that overlap showing there isn't a huge difference between those two groups. Some families don't overlap at all showing a significant difference between those two families. Some families have a wide spread of observations over the years, allowing for questions to be asked about the resilience of different soft coral families. Alcyoniidae for instance has a wide distribution across years that are overall high. This could indicate a high resiliance, but is still affected by a change in temperature

Figure 1. This boxplot shows how the distribution of observation for different soft coral families between 1996 and 2001. Most families have boxes that overlap showing there isn’t a huge difference between those two groups. Some families don’t overlap at all showing a significant difference between those two families. Some families have a wide spread of observations over the years, allowing for questions to be asked about the resilience of different soft coral families. Alcyoniidae for instance has a wide distribution across years that are overall high. This could indicate a high resiliance, but is still affected by a change in temperature

References

  • CSIRO National Collections and Marine Infrastructure (NCMI) Information and Data Centre (IDC): Surveys of Octocoral communities, benthic cover and environmental factors on coral reefs of the Great Barrier Reef, Australia (1996 to present) https://doi.org/10.15468/d0o0fe accessed via GBIF.org on 09-Feb-2021.

  • Data from the climate package available in R. That supplies hydrological and meteorological data for much of the world.I used it to find three stations where temperature data was taken at 2 meters for the years 1996-2001.

    • Czernecki, B.; Głogowski, A.; Nowosad, J. Climate: An R Package to Access Free In-Situ Meteorological and Hydrological Datasets for Environmental Assessment. Sustainability 2020, 12, 394. https://doi.org/10.3390/su12010394"